CSL  5.2
FFTReal.h
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1 /*****************************************************************************
2 * *
3 * DIGITAL SIGNAL PROCESSING TOOLS *
4 * Version 1.01, 1999/11/07 *
5 * (c) 1999 - Laurent de Soras *
6 * *
7 * FFTReal.h *
8 * Fourier transformation of real number arrays. *
9 * Portable ISO C++ *
10 * *
11 * Tab = 3 *
12 *****************************************************************************/
13 
14 #if defined (FFTReal_CURRENT_HEADER)
15  #error Recursive inclusion of FFTReal header file.
16 #endif
17 #define FFTReal_CURRENT_HEADER
18 
19 #if ! defined (FFTReal_HEADER_INCLUDED)
20 #define FFTReal_HEADER_INCLUDED
21 
22 #if defined (_MSC_VER)
23 #pragma pack (push, 8)
24 #endif // _MSC_VER
25 
26 class FFTReal {
27 
28 /*\\\ PUBLIC \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\*/
29 
30 public:
31  /* Change this typedef to use a different floating point type in your FFTs
32  (i.e. float, double or long double). */
33  typedef float flt_t;
34 
35  explicit FFTReal (const long length);
36  ~FFTReal ();
37  void do_fft (flt_t f [], const flt_t x []) const;
38  void do_ifft (const flt_t f [], flt_t x []) const;
39  void rescale (flt_t x []) const;
40 
41 /*\\\ PRIVATE \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\*/
42 
43 private:
44 
45  /* Bit-reversed look-up table nested class */
46  class BitReversedLUT {
47  public:
48  explicit BitReversedLUT (const int nbr_bits);
49  ~BitReversedLUT ();
50  const long * get_ptr () const {
51  return (_ptr);
52  }
53  private:
54  long * _ptr;
55  };
56 
57  /* Trigonometric look-up table nested class */
58  class TrigoLUT {
59  public:
60  explicit TrigoLUT (const int nbr_bits);
61  ~TrigoLUT ();
62  const flt_t * get_ptr (const int level) const {
63  return (_ptr + (1L << (level - 1)) - 4);
64  };
65  private:
66  flt_t * _ptr;
67  };
68 
69  const BitReversedLUT _bit_rev_lut;
70  const TrigoLUT _trigo_lut;
71  const flt_t _sqrt2_2;
72  const long _length;
73  const int _nbr_bits;
74  flt_t * _buffer_ptr;
75 
76 /*\\\ FORBIDDEN MEMBER FUNCTIONS \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\*/
77 
78 private:
79  FFTReal (const FFTReal &other);
80  const FFTReal& operator = (const FFTReal &other);
81  int operator == (const FFTReal &other);
82  int operator != (const FFTReal &other);
83 };
84 
85 #if defined (_MSC_VER)
86 #pragma pack (pop)
87 #endif // _MSC_VER
88 
89 #endif // FFTReal_HEADER_INCLUDED
90 
91 #undef FFTReal_CURRENT_HEADER
92 
93 /*****************************************************************************
94 
95  LEGAL
96 
97  Source code may be freely used for any purpose, including commercial
98  applications. Programs must display in their "About" dialog-box (or
99  documentation) a text telling they use these routines by Laurent de Soras.
100  Modified source code can be distributed, but modifications must be clearly
101  indicated.
102 
103  CONTACT
104 
105  Laurent de Soras
106  92 avenue Albert 1er
107  92500 Rueil-Malmaison
108  France
109 
110  ldesoras@club-internet.fr
111 
112 *****************************************************************************/
113 
114 /*\\\ EOF \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\*/